An LTCC system has a tailgate, a main gate and a cutter that travels between the main gate and tail gate, to cut coal from the long wall. The system also includes front and rear armored conveyors that travel beneath overhead shields, from the tailgate end, to deliver coal to a beam stage loader positioned adjacent the main gate. Each conveyor runs along a respective front or rear pan line and is driven by two motors, one at the tail gate end and one at the main gate end. The front conveyor carries coal cut by the cutter while the rear conveyor carries caved coal.
The shields protect the various components of the system and support the roof of the mine. The shields provide a continuous protective canopy over the length of the long wall, which may be up to 300 meters in length. Special buttress, gate and transition shields are provided toward each end of the system. The remaining run of face shields allow for caving, which is a distinguishing feature of the LTCC system. In particular, the shields are provided with a caving canopy and a slide door. The canopy can be lowered and the slide retracted to allow coal to cave onto the rear conveyor, after which the canopy can be returned to its original position.
With existing LTCC systems, the caving operation is conducted manually, on each individual shield in turn. After each cutting cycle, the shields are moved forward, the caving is then completed and the rear pan line is pulled forward in line with the shields, ready for the next cutting cycle. As may be appreciated, the entire process is relatively time consuming and the output of coal during the caving cycle varies dramatically. The volume of coal output from the caving cycle is also considerably less overall compared to the coal extracted during the cutting cycle.